1. Field of the Invention
The invention relates to providing information regarding location of a mobile user equipment, and in particular to communication of various information when providing location information.
2. Description of the Related Art
Various services can be provided for a user of a mobile user equipment by means of a communication system. Recent development in the field of mobile user equipment has lead to arrangements wherein information about a location of a mobile user equipment is determined and utilized when providing services for the user equipment and/or other parties. Such services may sometimes be called location sensitive services.
A mobile user equipment may comprise, for example, a mobile telephone, a laptop computer, a personal data assistant or any other user equipment enabled for wireless communication with another station. An example of a communication system providing mobility for users thereof is the public land line mobile network (PLMN) or cellular network. Another example is a mobile communication system that is based, at least partially, on use of communication satellites. Wireless communications may also be provided by means of other arrangements, such as by means of wireless local area networks (WLAN).
The skilled person is aware of the basic principles of a wireless communication system. A wireless communication system typically operates in accordance with a given standard or specification which sets out what the various elements of the system are permitted to do and how that should be achieved. For example, the standard or specification may define if the user, or more precisely, user equipment or terminal is provided with a circuit switched service or a packet switched service or both. Communication protocols and/or parameters which shall be used for the connection are also typically defined. For example, the manner how communication shall be implemented between the user equipment and the elements of the communication network is typically based on a predefined communication protocol. In other words, a specific set of “rules” on which the communication can be based on needs to be defined to enable communication by means of the communication system.
A communication system needs to be able to provide various different functions in order be able to operate. These functions can be divided in different categories. A category comprises functions that relate to the actual carrying of communications such as voice or multimedia or other data content in the system. Another category can be seen as being formed by control or management functions such as the control of various services and the actual communication. Signaling associated with different functions is thus understood as being carried on different planes. For example, control messages are communicated on a control plane and the actual communication is transported on a user plane. The communication on the user plane is supported the signaling of the control messages on the control plane. The predefined rules commonly dictate the appropriate plane that shall be used for communication.
Typically the communication systems provide the different planes by means of separate channels, e.g. by means of separated signaling and communication channels. Such arrangements are employed e.g. by signaling system 7 (SS7) core networks and Q.931/GSM/WCDMA subscriber access. Therefore the term signaling channel may be used when referring to control plane communications. Similarly the term communication channel may be used when referring to user plane communications.
The various functions of communication systems may have developed quite independently from each other. Different protocols may also be used in different communication systems. The standards and protocols define e.g. which plane shall be used for a certain purpose.
The mobile network apparatus and/or user equipment can be employed for providing information regarding the geographical location of the user equipment and thus the user thereof. In addition to location in the home network of a user, it is also possible to determine information about the geographical location of a user equipment when the user equipment is located outside the home network, i.e. when the user equipment is located in a coverage area of a visited or “foreign” network. The visited network may either transmit the location of the mobile user equipment back to the home network or the information may be used locally in the visited area.
A mobile user equipment and thus the user thereof can be positioned by various different techniques. For example, substantially accurate geographical location information that associates with a user equipment can be obtained based on a satellite based positioning system, for example the GPS (Global Positioning System) or Galileo. More accurate location information can be obtained through a differential GPS or an assisted GPS (A-GPS). In an approach the cells or similar geographically limited radio access entities and associated controllers of the communication system are utilized in production of an estimate concerning the location of a mobile user equipment. To improve the accuracy of the location information the communication system may be provided with additional equipment, for example specific location measurement units (LMUs), that provide more accurate data or additional data that may be used when determining a location of a mobile user equipment.
Location information may be used for various purposes, such as for location of a mobile telephone that has made an emergency call or for other call related services, for locating given mobile subscribers for commercial purposes and so on. In general, a client (for example a user or a network entity wanting to receive location information regarding a user may) may send a request for location information to a location service entity. The location service entity may be, for example, a location service server provided in the network or the target user equipment itself. An appropriate location service entity may then process the request, obtain the required data and generate an appropriate response.
Communication associated with location services may be signaled on the control plane or the user plane. The selection of the plane depends on the application. That is, the location service associated communications to and from a user equipment may occur either on a control plane or a user plane.
Applications that use control plane for communication of information for location determination commonly employ embedded signaling protocols. However, this may cause relatively high load on the control plane. The high loading may cause problems especially on the air interface between a mobile user equipment and a radio network servicing the mobile user equipment.
Thus it has been proposed that a mobile user equipment could be located by using user plane signaling for communications of location services information. Some of user plane applications are a kind of overlay solutions wherein a data connection is established on a user plane between a relevant server and a mobile user equipment to transfer on radio interface information that is needed in location determinations. The user plane data connection may be a dedicated connection established for communication of location information. In another approach location information may be communicated on a user plane connection established for other purposes. The user plane signaling may be based on appropriate communication protocol, for example the Internet Protocol (IP) or data messages such as short message service (SMS) messages. Data may need to be transferred from a user plane enabled server to a user equipment and/or from a user plane enabled server to a user equipment. An example of the proposals presented in Open Mobile Alliance (OMA) wherein user plane is used is known by the work name ‘Secure User Plane Location’ (SUPL).
Communications on the user plane commonly occur transparently for the underlying access network systems. In other words, the radio access network (RAN) may not be aware of the type of the user plane communications. This may be problematic, for example if the communications relate to location services and/or calls to emergency numbers. If a location service of a communication system is based on user plane communications, triggering of locations services for a specific connection, for example for an emergency call, may not be possible. The user plane location service communications and control plane communications of the emergency cannot be associated to each other because there is no suitable interface for this purpose. Because of the lack of the interface the user plane location service entity may not be able to identify the origin of an emergency call, and thus cannot know the target of location determinations. Therefore a mechanism that enables triggering of location services for certain types of connections even if user plane communications are used for communication of information during the location determination procedure might prove to be useful.